In the electronic sensing market, there are a wide variety of sensors for sensing objects at a given location. Such sensors are configured to sense electronic characteristics of an object in order to sense presence of an object near or about the sensor and other features and characteristics of the object being sensed.
Sensors may be configured to passively detect characteristics of an object, by measuring parameters such as temperature, weight, or various emissions such as photonic, magnetic or atomic emissions of an object in close proximity or contact with the sensor. An example of this is a non-contact infrared thermometer that detects the black body radiation spectra emitted from an object, from which its temperature can be computed.
Other sensors work by directly exciting an object with a stimulus such as voltage or current, then using the resultant signal to determine the physical or electrical characteristics of an object. An example of this is a fluid detector consisting of two terminals, one that excites the medium with a voltage source, while the second measures the current flow to determine the presence of a conductive fluid, such as water.
A two dimensional array of impedance data may be created by moving an object over a line sensing array and then performing a line by line reconstruction of a two dimensional image. An example of this is a swiped capacitive fingerprint sensor that measures differences in capacitance between fingerprint ridges and valleys as a finger is dragged across it. Such sensors reconstruct a two dimensional fingerprint image after the fact using individual line information.
A simpler way to obtain a two dimensional image is to create a two dimensional sensing array. Such sensors, however, can be prohibitive in cost due to the large number of sensing points needed in the array. An example of this is a two dimensional capacitive fingerprint sensor. A number of these are currently manufactured but use 150 mm2 or more of silicon area and are therefore cost prohibitive for many applications.
These different types of electronic sensors have been used in various applications, such as biometric sensors for measuring characteristics such as fingerprints, medical applications, or fluid measuring monitors. Typically, sensing elements of the various devices are connected to a processor configured to process object information and to enable interpretations for object features.
There exists a need in the art for a device that can provide accurate and reliable sensors for use in different applications, such as fingerprint sensing and/or authentication.